Thermosetting compositions and molding method

ABSTRACT

A thermosetting resin containing composition can be heated to reduce its viscosity and used as a liquid in a liquid injection molding method. It has a phenolic resin content of about 80% to about 90% solids by weight, and contains about 5% to about 40% of a polyglycol. The composition may also contain resorcinol as a compatibilizing agent and a polyalkylene glycol as the polyglycol agent. In a novel method the resin containing composition is heated to reduce its viscosity and introduced into a heated mold in a liquid injection molding method.

This is a division of application Ser. No. 07/290,785, filed Dec. 28,1988, now U.S. Pat. No. 4,880,893.

FIELD OF THE INVENTION

The invention relates generally to thermosetting resins. Moreparticularly, it relates to composition containing phenolic resins and amethod for their use in injection molding.

BACKGROUND OF THE INVENTION

Thermosetting compositions, such as phenolic resins, have been known formany years and have been used in many applications because they havehigh heat resistance; they are light weight; they have excellentdimensional stability and they have very low flammability. The usualmethod for preparing thermoset molding compounds involves blending theresin with fillers, pigments and other additives, followed bycompounding and granulating. The granulated resin compositions are thenfabricated by any of the known methods such as compression, transfer, orinjection molding.

Recently, there have been developed new fabrication methods in whichliquid thermosetting resin compositions are injected directly into amold where curing takes place, resulting in the formation of afabricated part. Depending on the process steps and the nature of thecompositions, these methods are known as liquid injection molding (LIM),reaction injection molding (RIM), or resin transfer molding (RTM).Liquid thermosetting resins also may be employed in sheet-moldingcompound (SMC) or pultrusion (PT) processes.

The liquid injection molding processes are fast and adaptable to highspeed production requirements, and since the curing reaction isgenerally exothermic, these processes are less energy intensive than theusual methods for processing thermosetting resins. In addition, liquidinjection offers the potential of precise orientation of reinforcingfibers in the mold prior to injection of the resin. This allows theproduction of parts with maximized strength to achieve engineeringobjectives. However, attempts to use these processes in the fabricationof products using conventional phenolic resins have not been completelysuccessful because of the excess shrinkage of low solids content resins,and the residual unbound water and volatile organic impurities which maybe present in the resins.

The presence of excess water and/or volatile organic compounds in theresins can result in problems by causing undesirably high mold pressureand formation of voids or bubbles in the formed composite, resulting ina loss of clarity and strength of the resin composite. Thus, many lowersolids content, phenolic thermosetting compositions are unsuitable forliquid injection processes.

Attempts to use high solids content phenolic resins also have beenrelatively unsuccessful because of the high viscosity of such resins andthe presence of voids in the formed composite. The high viscosity ofsuch resins, many of which are solid or nearly solid at roomtemperature, necessitates high shear mixing with any reinforcingmaterial and injection into the mold under high shear conditions. Thiscan result in significant attrition of the reinforcing material, thuslowering the strength of the final composite. Such premixing alsoprecludes the use of resin transfer molding. The high viscosity of suchresins also impedes sufficient wetting of the reinforcing material andadequate mixing with the reinforcing material. The end result is usuallyproducts which have poor physical properties, including areas in whichthere is separation of the resins from the reinforcing materials.

As previously described, phenolic resins are known for their hightemperature mechanical strength, low flammability resistance and solventresistance. Therefore, it would be highly desirable to have phenolicresin composition that do not possess the above described disadvantagesand could be used in liquid injection molding methods.

BRIEF SUMMARY OF THE INVENTION

The primary objects of the present invention are to disclose novelliquid injection molding compositions having high solids content ofphenolic thermosetting resins and an improved method of liquid injectionmolding using such compositions.

The novel compositions of the present invention contain from about 80percent to about 90 percent solids by weight of a phenolic resin havinga formaldehyde to phenol ratio of about 1.0:1 to 2:1 and an effectiveamount, about 5 percent to about 40 percent by weight, of a polyglycolwhich reduces bubbles or voids and improves clarity and strength of thefinished product. The compositions may also contain an effective amountof a compatibilizing agent, such as a reactive phenol, which reduces theamount of acidic catalyst required and improves curing time. The novelcompositions have a viscosity of about 200 centipoise to about 10,000centipoise at a temperature of about 80° C.

Molded products formed by the curing of the compositions of the presentinvention are clear and relatively free of voids. In addition, if acompatibilizing agent, such as a reactive phenol (e.g. resorcinol) isincluded less acidic catalyst can be employed. Thus, the finishedproducts will have less residual acidity and correspondingcorrosiveness.

In the preferred method, a novel composition of the present invention isheated to a temperature which causes a reduction in viscosity whichallows the composition to be injected or transferred into a heated moldwhich may contain filler. Preferably, the compatibilizing agent andcatalyst are dissolved in the polyglycol and the resulting mixture addedto the liquid resin component prior to injecting the composition intothe heated mold. The composition is then cured with or without addedheat.

The phenolic resin resole component of the compositions of the presentinvention may be any conventional phenolformaldehyde resin resole whichhas a formaldehyde to phenol ratio of 1.0:1 to 2:1, preferably about1.15 to 1.4:1, and which is curable to a solid crosslinkedphenol-formaldehyde solid resin. The resin resole should be one that canbe liquified to a suitable viscosity by heating and which will remain ata suitable viscosity for the required time under the molding conditions.Suitable resin resoles are disclosed in U.S. Pat. No. 3,485,797, issuedto Robins on Dec. 23, 1969.

The formaldehyde ingredient of the preferred resin resole may beintroduced to the reaction mixture as aqueous formaldehyde solution oras paraformaldehyde. Although the preferred resin contains formaldehyde,it is well known in the art that other aldehydes such as acetaldehyde,propionic aldehyde, butylaldehyde and furfural can be substituted forformaldehyde in phenol-formaldehyde type resins. However, in order thathydroxymethyl groups can form, some formaldehyde should be present inthe reaction mixture wherein the compositions of the invention areformed. At least 20 mole percent formaldehyde, based on the total molesof aldehyde used, should be sufficient formaldehyde to form thehydroxymethyl groups.

The phenols suitable for use in the resin component are phenol per se,substituted phenols and mixtures thereof. Preferably the mixturescontain phenol. Suitable phenols can be represented by the formula;##STR1## where X and a are defined above, and wherein at least two ofthe ortho- and para-positions relative to the hydroxy group are free.Most preferably the substituents should be in the meta-positions only,leaving the ortho- and para-positions free. Examples of suitablesubstituted phenols are cresols, isopropylphenols, nonylphenols ordihydric phenols, such as bis-phenol A, bis-phenol F, hydroquinone andresorcinol. Use of substituted phenols will tend to alter the propertiesof any resulting phenolic resin which is derived from the resultingproduct, such property changes being of the kind which allows for amaximum variety of phenolic resin product types. For example, a halogensubstitution will enhance the flame retardancy of the resultant phenolicresin. Also a diphenol such as bisphenol A has an additional phenolichydroxy group, providing another site for hydroxymethyl group ormethylol group production.

The total aldehyde to total phenol molar ratio should be from about1.0:1 to 2:1, preferably 1.1:1 to 1.4:1.

The preferred polyglycols are polyethylene glycol and polypropyleneglycol. They can be added in amounts ranging from about 5% to about 40%by weight without reducing the clarity hardness of the molded part. Theexact concentration, of course, depends upon the resin and projectedwater content. In a preferred embodiment, the percent of polyglycol willbe from about 5% to about 30% by weight. The polyglycol improves thetranslucency of the finished product presumably by nullifying theeffects of any residual water that is present. It is believed that thepolyglycol helps compatibilize the water with the resin which growsincreasingly incompatible as it goes toward complete cure.

Also, if desired, there may be added to the resin resole other types ofpolymers which can co-cure with these reactive compositions. Examples ofco-reactive polymers are phenol-formaldehyde resoles, andphenol-formaldehyde novolacs of either the high ortho or nominal orthocontent. The use of these additives serves either to modify theproperties of the cured product or the handling characteristics of theprepolymer.

The reinforcing materials or fillers suitable for use in the novelcompositions of the present invention include those typically used inthe manufacture of reinforced composites, such as glass fibers, carbonfibers, graphite fibers, ceramic fibers, wollastonite, cellulosic fiberssuch as wood flour and the like, organic fibers such as aromaticpolyamide fibers, and mica. The preferred reinforcing materials areglass fibers, carbon fibers, graphite fibers and aromatic polyamidefibers.

Products can be made by any of the liquid injection molding processes,such as LIM, RIM, RTM or PT. The RTM and PT methods, are especiallypreferred.

In one modification of the pultrusion method, the reinforcing materialis introduced into a heated mold, the novel composition is liquified byheating and injected into the mold and cured. The finished product ispulled from the mold using the reinforcing material.

The preferred compositions also contain a compatibilizing agent, such asa reactive phenol derivative, which is capable of reducing the amount ofacid catalyst and/or curing temperature. Resorcinol which is non-acidicand noncorrosive to molds is especially preferred. The resorcinol may beused in an amount ranging from 2% to about 30% by weight of the resin.Especially preferred is an amount of resorcinol of about 5% to 15%.Resorcinol containing novolacs and resorcinol containing resoles may beused in some instances in place of pure resorcinol. Other reactivephenol derivatives that can be employed include pyrogallol, catechol,m-aminophenol and m-cresol.

In general, although non-acidic catalysts are preferred, all thosecatalysts which are commonly employed for the cure ofphenol-formaldehyde resins can be used to cure the novel composition.Typical acid catalysts are sulfuric acid, sulfonic acids such asphenolsulfonic acid, oxalic acid, boron trifluoride, boric anhydride,boric acid and mixtures of boric acid or boric anhydride with epoxies.Latent catalysts also can be used and include certain phenyl esters ofcarboxylic acids that form upon cure a carboxylic acid having a pKa of 2or less. Also included are sulfur dioxide containing compounds thatgenerate sulfur dioxide at cure conditions. Examples of latent catalystsinclude phenyl hydrogen maleate, phenyl trifluoroacetate and butadienesulfone. Additional basic catalysts are the organic amines such ashexamethylenetetramine, trimethylamine, ethanolamines and oxides andhydroxides of metals such as barium, calcium, sodium and potassium.

The compatibilizing agent and catalyst can be dissolved in thepolyglycols and the mixture introduced into the liquid resin componentimmediately before injection into the mold.

The concentration of the catalyst depends on cure rate required and acidor base strength of the catalyst. For a strong acid such as sulfuricacid, the typical concentration is from 0.01 weight percent to 5 weightpercent. For weaker acids or bases concentrations as high as 10-15weight percent can be employed The latent catalysts are typically usedin an amount from about 0.2 to about 10 weight percent, preferably about0.5 to about 5 weight percent. The basis of the percentages is theweight of the catalyst free resin. Due to the ease of obtaining ahomogeneous polymerizing mixture, catalysts soluble in the liquifiedresin of the invention are preferred.

The compositions of the present invention may be cured by theapplication of heat. The curing temperature can be the same or lowerthan the temperature of the injected composition provided it remainsliquid long enough for the molding process. Usually a curing temperatureof about 100° C. to about 200° C. is employed. The curing time can beregulated by type and concentration of the catalyst and will varydepending on such factors as the particular composition of thethermosetting resin, the fabrication process, the configuration of thecured part and other factors known to those in the art. When used inliquid injection molding applications, the cure time is generally fromabout 1 to about 10 minutes.

The following examples serve to further illustrate the invention.Examples 1 to 6 describe the preparation of high solids content phenolicresin components; Example 7 describes the preparation of prepregs ofresin and filler; Example 8 describes efforts to optimize theconcentrations of the resorcinol and the polyglycol; Example 9 describesthe preparation of a prepreg using the compositions of the presentinvention; Example 10 describes the use of sodium hydroxide as thecatalyst; and, Example 11 illustrates the method of the presentinvention. The examples are not intended to limit the invention in anyway.

In the examples, the following standard evaluation procedures wereemployed:

    ______________________________________                                        Flexural Modulus      ASTM D790                                               Flexural Strength     ASTM D790                                               Notched Izod (Impact) ASTM D256                                               Heat Deflection Temperature (HDT)                                                                   ASTM D648                                               Tensile Modulus       ASTM D638                                               Tensile Strength      ASTM D638                                               Elongation            ASTM D638                                               ______________________________________                                    

Example 1 The Manufacture of High Solids Content Phenolic Resin MoleRatio 1.266 Moles Formaldehyde/Mole of Phenol

Into a 4 liter stainless steel resin flask, equipped with a stirrer,reflux condenser and thermometer, was charged 1500 grams (15.96 moles)USP phenol, 1170 grams (20.2 moles) 52% formaldehyde, and 120 grams of25% tetramethylammonium hydroxide in water. The solution was stirred andheated to 90° C over a period of 46 min. The batch was then held at 90°C for 1 hr. At the end of this period, the reflux condenser wasexchanged for a vacuum distillation condenser and receiver and 28" ofvacuum slowly applied. The batch was then distilled at 28" of vacuum toa batch temperature of 80° C. The distillation phase required 3 hrs 15min. The resin was then cooled to room temperature and discharged.Measurement of the resins' properties yielded the following results:

    ______________________________________                                        Yield in grams            2055                                                Viscosity, Brookfield, cps, 25° C.                                                               7750                                                Specific Gravity, 25° C.                                                                         1.184                                               Solids Content, 3 hrs @ 135° C.                                                                  82.6%                                               Moisture Content, %       1.58                                                Free Formaldehyde in the Resin, %                                                                       1.55                                                Number Average Molecular Weight                                                                         139                                                 Weight Average Molecular Weight                                                                         173                                                 ______________________________________                                    

Example 2 The Manufacture of High Solids Content Phenolic Resin MoleRatio 1.639 Moles Formaldehyde/Mole of Phenol

Into a 4 liter stainless steel resin flask, equipped with a stirrer,reflux condenser and thermometer, was charged 1500 grams (15.6 moles)USP phenol, 1500 grams (26 moles) 52% formaldehyde, and 120 grams of 25%tetramethylammonium hydroxide in water. The solution was stirred andheated to 90° C. over a period of 50 min. The batch was then held at 90°C. for 1 hr. At the end of this period the reflux condenser wasexchanged for a vacuum distillation condenser and receiver and 28" ofvacuum slowly applied. The batch was then distilled at 28' of vacuum toa batch temperature of 80° C. The distillation phase required 3 hrs 20min. The resin was then cooled to room temperature and discharged.Measurement of the resins' properties yielded the following results:

    ______________________________________                                        Yield in grams            2280                                                Viscosity, Brookfield, cps, 25° C.                                                               29200                                               Specific Gravity, 25° C.                                                                         1.212                                               Solids Content, 3 hrs @ 135° C.                                                                  84.7                                                Moisture Content %        1.64                                                Free Formaldehyde in the Resin, %                                                                       3.15                                                Number Average Molecular Weight                                                                         160                                                 Weight Average Molecular Weight                                                                         243                                                 ______________________________________                                    

Example 3 The Manufacture of High Solids Content Phenolic Resin MoleRatio 2.03 Moles Formaldehyde/Mole of Phenol

Into a 4 liter stainless steel resin flask equipped with a stirrer,reflux condenser and thermometer, was charged 1500 grams (15.96 moles)USP phenol, 1866 grams (32.3 moles) 52% formaldehyde and 120 grams of25% tetramethylammonium hydroxide in water. The solution was stirred andheated to 90° C. over a period of 46 min. The batch was then held at 90°C. for 1 hr. At the end of this period the reflux condenser wasexchanged for a vacuum distillation condenser and receiver and 28" ofvacuum slowly applied. The batch was then distilled at 28" of vacuum toa batch temperature of 80° C. The distillation phase required 3 hrs 15min. The resin was then cooled to room temperature and discharged.Measurement of the resins' properties yielded the following results:

    ______________________________________                                        Yield in grams            2345                                                Viscosity, Brookfield, cps, 25° C.                                                               63500                                               Specific Gravity, 25° C.                                                                         1.259                                               Solids Content, 3 hrs @ 135° C.                                                                  85.5                                                Moisture Content, %       1.79                                                Free Formaldehyde in the Resin, %                                                                       5.81                                                Number Average Molecular Weight                                                                         177                                                 Weight Average Molecular Weight                                                                         280                                                 ______________________________________                                    

Example 4 The Preparation of a Solid Resole Resin

Into a 4 liter stainless resin kettle, equipped with an anchor agitator,reflux condenser and thermometer, was added 1500 grams (15.96 moles)phenol, 1200 grams (20.8 moles) 52% formaldehyde. To this solution wasthen added 7.0 grams (0.175 mole) of caustic soda and 22.9 grams (0.164mole) of hexamethylenetetramine. This mixture was brought to 90° C. overa period of 40 min and maintained at this temperature for an additional35 min. At the end of the holding period 26" of vacuum was slowlyapplied. The batch was distilled at 26" of vacuum to a temperature of90° C, at which point the vacuum was increased slowly to 28" where itwas held until the viscosity, as measured by watt meter reading on theagitator drive, reached 120 watts at a speed setting of 5. The resin wasthen discharged to a cooling plate to cool. The yield was determine tobe 1809 grams.

Measurement of the melting point of the resin, by gradient bar methods,gave a value of 170° F. and a stroke cure of 23 sec at 330° F.

Example 5 The Preparation of a Resorcinol-Phenol-Formaldehyde Novolac

Into a 4 liter stainless resin flask equipped with a thermometer,agitator, reflux condenser, and addition port, is placed 900 grams (9.6mole) phenol, 534 grams (9.12 mole) 52% formaldehyde, 200 grams water,and 10 grams of oxalic acid dissolved in 20 grams of hot water. The pHwas found to be 1.0. The mixture was then brought to 80° C. in 22 minand the heat removed. An exothermic reaction then carried the reactiontemperature to 101° C. where reflux occurred. The reacting mass was heldat reflux for 20 min, then cooled to 20° C. When a batch temperature of20° C. was reached, 400 grams (3.6 mole) of resorcinol was added. Thebatch was then heated to 35° C. at which temperature a mild exothermensued raising the temperature to 70° C. over a 11 min period. Refluxwas attained only upon the addition of extra heat and it was continuedfor an additional one-half hour. At this point, an additional 9.5 gramsof oxalic acid dissolved in 19 grams of hot water was added and refluxcontinues for an additional 2 hrs. The excess oxalic acid was thenneutralized by the addition of 7.0 grams of calcium hydroxide as aslurry in 14 grams of water, and the reaction mass distilled atatmospheric pressure to a temperature of 150° C. The resin was poured toyield 1345 grams of resin. The product was found to melt on a heatedgradient bar at 184° F. and have a set time when blended with 10%hexamethylenetetramine of 7-9 seconds.

Example 6 The Preparation of a Resorcinol Based Resole Resin

Into a 4 liter stainless kettle, equipped with a reflux condenser,stirrer, thermometer and addition port, are placed 940 grams (10 moles)phenol, 105 grams barium hydroxide octahydrate dissolved in 400 grams ofwater, and 1385 grams (24 moles) formaldehyde 52%. The mixture washeated to 85° C. in 21 min and held for 1-hr with good agitation. At theend of this holding period 660 grams (6 moles) of resorcinol was slowlyadded over a 30 min period. When the addition of resorcinol wascomplete, 128 grams of 20% sulfuric acid was added to adjust the pH to7.55. When the pH was reached, the reaction mixture was distilled at 28"of vacuum to 56° C. The distillation step required 2 hrs 46 min. Thefinished resin was discharged to a storage container and found to weigh2354 grams. The properties we found are as below:

    ______________________________________                                        Brookfield Viscosity @ 25° C., cps                                                               656,000                                             Solids Content, 3 hrs @ 135° C.                                                                  87%                                                 Moisture Content, %       6.5                                                 Free Formaldehyde Content, %                                                                            0.09                                                Set Time @ 330° C., sec                                                                          25                                                  ______________________________________                                    

Example 7 The Preparation of a Press Laminate of Phenolic Bonded 4533 SGlass

A solution of the solid resole from Example 4 was prepared by dissolving500 grams of this product in 500 grams of ethanol. This solution wasthen used to coat 19 sheets of 4533 S-glass cloth. After each treatmentthe excess resin was wiped repeatedly over the surface with a rubberwiper blade to assure good penetration, and the excess wiped off. Theindividual sheets were allowed to dry at room temperature for 12 hrs andwere then advanced by oven drying at 70° C for 1 hr. The sheets werethen stacked between two polished steel sheets and molded at 500 psi for5 min at 300° F. From the laminate so formed, tensile specimens were cutaccording to the dimension given in ASTM D638. These were testedaccording to that test and found to possess a tensile strength of 40,510psi.

Similarly, a laminate of 27 sheets was made and molded at 800 psi for 7min at 300° F. These were cut to standard ASTM D790 flexural strengthspecimen measuring 1/2"×1/8"×5". Testing of these specimens yielded aflexural strength of 36,981 psi. Ash testing of the broken samplesshowed both samples to contain 30% resin, 70% glass fabric. To attemptto determine the effect of resin loading on the strength, a separateexperiment was performed in which the glass cloth was treated twice withresin and allowed to dry between resin application. In this way, theresin content of the laminate was increased to 55%. This gave a flexuralstrength of 34,659 psi, which was only slightly inferior to the resultson the higher loading sample.

Example 8 Preparation of Test Samples to Determine Optimum Catalyst andAdditive Concentrations

In an effort to determine optimum concentrations of resorcinol andpolyethylene oxide, it was determined to vary the polyethylene contentbetween 0 and 25 parts per hundred weight of resin and the resorcinolconcentration over the same range. As there may be a dependence of theproper amount of each additive upon the ratio of formaldehyde to phenolused in the manufacture of the resin, each resin as described inExamples 1, 2 and 3 had to be compared in the same test protocol. Toachieve this, the following table which shows percents by weight wasprepared:

    __________________________________________________________________________    Parts PEG per                                                                          Parts Resorcinol per 100 Parts of Resin                              100 parts of resin                                                                     5         15         25                                              __________________________________________________________________________     5       Resin 90.90%                                                                            Resin 83.33%                                                                             Resin 76.92%                                             PEG   4.545%                                                                            PEG   4.1667%                                                                            PEG   3.85%                                              Resorcinol                                                                          4.545%                                                                            Resorcinol                                                                          12.50%                                                                             Resorcinol                                                                          19.23%                                    15       Resin 83.33%                                                                            Resin 76.92%                                                                             Resin 71.43%                                             PEG   12.50%                                                                            PEG   11.54%                                                                             PEG   10.71%                                             Resorcinol                                                                          4.7%                                                                              Resorcinol                                                                          11.54%                                                                             Resorcinol                                                                          17.86%                                    25       Resin 76.92%                                                                            Resin 71.43%                                                                             Resin 66.67%                                             PEG   19.23%                                                                            PEG   17.86%                                                                             PEG   16.67%                                             Resorcinol                                                                          3.85%                                                                             Resorcinol                                                                          10.71%                                                                             Resorcinol                                                                          16.67%                                    __________________________________________________________________________

As mentioned above, each of the three resins was examined in each of thenine formulations, using a catalyst consisting of a mixture of 17.5water, 32.5% phenol sulfonic acid, and 50.0% polyethylene glycolmolecular weight 200. Resin from Example 1 was prepared with the lowestmole ratio; Example 2 the intermediate mole ratio; and Example 3 thehighest mole ratio.

The result will be displayed in the same fashion as above, that is, in amatrix of nine blocks. The following tables show that an increase inresorcinol content shortens gel time.

    ______________________________________                                                   Gel Time at 7% Catalyst @ 80° C.                            Parts PEG per                                                                            Resorcinol, pph                                                    100 parts of resin                                                                       5          15          25                                          ______________________________________                                         5         Ex. 3  5 min   Ex. 3                                                                              <1 min Ex. 3                                                                               --                                           Ex. 2  5 min   Ex. 2                                                                              10 min Ex. 2                                                                               --                                           Ex. 1  8 min   Ex. 1                                                                              4 min  Ex. 1                                                                               --                                15         Ex. 3  6 min   Ex. 3                                                                              3 min  Ex. 3                                                                              1 min                                         Ex. 2  8.5 min Ex. 2                                                                              5 min  Ex. 2                                                                              1 min                                         Ex. 1  6 min   Ex. 1                                                                              3.5 min                                                                              Ex. 1                                                                              2 min                              25         Ex. 3  5.5 min Ex. 3                                                                              4 min  Ex. 3                                                                              1 min                                         Ex. 2  4 min   Ex. 2                                                                              1 min  Ex. 2                                                                              2 min                                         Ex. 1  10 min  Ex. 1                                                                              2.5 min                                                                              Ex. 1                                                                              3 min                              ______________________________________                                                   % Acid Catalyst to Deliver                                                    10 minute Cure @ 80° C.                                     Parts PEG per                                                                            Resorcinol pph Resin                                               100 parts of resin                                                                       5          15          25                                          ______________________________________                                          5        7.5%       6%          --                                          15           7%       6%          5.8%                                        25         6.7%       6%          5.5%                                        ______________________________________                                    

The tables report on the effects of resorcinol content on appearance andclarity.

    __________________________________________________________________________              Resin Clarity of Casting at 5% Catalyst Level                       Parts PEG per                                                                           Resorcinol, pph                                                     100 parts of resin                                                                      5        15       25                                                __________________________________________________________________________     5        Ex. 3                                                                            Milky Ex. 3                                                                            Stress                                                                              Ex. 3                                                                             --                                                                  Cracked                                                           Ex. 2                                                                            Milky Ex. 2                                                                            Milky Ex. 2                                                                             --                                                      Ex. 1                                                                            Milky Ex. 1                                                                            Milky Ex. 1                                                                             --                                            15        Ex. 3                                                                            Milky Ex. 3                                                                            Stress                                                                              Ex. 3                                                                            Milky spots                                                          Cracked                                                           Ex. 2                                                                            Clear/                                                                              Ex. 2                                                                             --   Ex. 2                                                                            Clear                                                       Rubbery                                                                    Ex. 1                                                                            Clear Ex. 1                                                                            Clear Ex. 1                                                                            Clear                                          25        Ex. 3                                                                            Milky Ex. 3                                                                            Stress                                                                              Ex. 3                                                                            Clear/some                                                           Cracked  stress                                                   Ex. 2                                                                            Stress                                                                              Ex. 2                                                                            Milky clear                                                                         Ex. 2                                                                            Clear                                                       Cracked                                                                    Ex. 1                                                                            Clear/                                                                              Ex. 1                                                                            Clear/some                                                                          Ex. 1                                                                            Clear/some                                                  Rubbery  stress   stress                                         __________________________________________________________________________              pH of Resin @ 5% Catalyst                                           Parts PEG per                                                                           Resorcinol, pph                                                     100 parts of resin                                                                      5        15       25                                                __________________________________________________________________________     5        3.56     4.23                                                                 4.92     3.74                                                                 6.85     6.16                                                       15        3.74              4.34                                                        4.60     3.90     3.93                                                        5.96     6.43     6.16                                              25        3.50     3.72     3.0                                                         3.76     2.87     3.64                                                        6.93     6.55     6.13                                              __________________________________________________________________________

Example 9 Composite Strength Comparison

The resins prepared in Examples 1, 2, and 3 were converted intocomposite specimen blanks by the wet layup technique. This was done byadding 75 grams resorcinol, 25 grams polyethylene oxide molecular weight200, and 9.75 grams of phenol sulfonic acid to 600 gms of resin. Whenthe compounds were thoroughly mixed with the resin, 27 sheets of 4533S-glass were layered up with the resin to prepare blanks for flexuralspecimens. In the preparation of tensile specimen blanks, 19 sheets ofglass cloth were used. Both layups were made with 12"×12" sheets ofglass cloth directly onto a waxed glass plate and a cover plate placedon top forming a sandwich of layed-up glass cloth between two glassplates. The ensemble was then placed in an oven at 80° C. overnight. Inthe morning the ensemble was removed, disassembled, and the compositeallowed to cool. When cool, tensile and flexural specimens were cut fromthe appropriate blanks and conditioned as per the ASTM Test Methods D638and D790. The specimens were then tested to give the following results:

    ______________________________________                                                   Example 1                                                                              Example 2 Example 3                                       ______________________________________                                        Tensile Strength, psi                                                                      45,712     24,809    32,307                                      Flexural Strength, psi                                                                     48,189     14,896    34,005                                      ______________________________________                                    

Example 10 Use of Sodium Hydroxide Catalyst

The procedure of Example 9 was repeated using 1% sodium hydroxide as thecatalyst. The results obtained were comparable to those of Example 9.

Example 11 Molding Process

The resin compositions described in Example 9 were heated to 80° C. toreduce their viscosity and injected into a heated mold (temperature 80°C.) for a miniature boat-like structure. The compositions were cured byheating the mold to about 100° C. The finished products were relativelyfree of voids and comparable in strength to products made from epoxybased compositions.

It will be readily apparent to those skilled in the art that a number ofmodifications and changes may be made without departing from the spiritand scope of the invention. Therefore, the invention is not to belimited except by the claims.

I claim:
 1. A liquid catalyst composition for use in curing a phenolicresin, said composition comprising an effective amount of a catalyst forcuring a phenolic resin in a liquid containing at least about 50% byweight of a liquid polyglycol, said effective amount of a catalyst beingselected from up to 5 weight percent of a strong acid catalyst up to 15weight percent of a weak acid catalyst, up to 10 weight percent of alatent catalyst, and up to 15 weight percent of a basic catalyst, saidweight percent being the percent by weight of the catalyst free phenolicresin.
 2. A catalyst composition of claim 1 in which the polyglycol isselected from polyethylene glycol and polypropylene glycol.
 3. Acatalyst composition of claim 1 in which the catalyst is sulfuric acid.4. A catalyst composition of claim 1 in which the catalyst is sodiumhydroxide.
 5. A catalyst composition of claim 1 which also contains areactive phenol compatibilizing agent.